When I tested it regarding photoshop, I found the same result for the same transformations at the same resolution (translating, rotating, scaling, and combining multiple ones). I also heard that tvpaint and adobe have kind of the same algorythm seems legit to me.
Personnally I sometimes use "none" as a setting instead of "smart" cause I find it beter looking at the end, even with the aliasing. Fabrice told me back in the days that the "best" mode is essentially for photos.
Here are the main reasons why photoshop seems to have a better algorythm :
- You usually work in much greater canvas in photoshop than in tvpaint. 1080 and A4 300dpi doesn't have the same pixels to work with...
- Because of the resolution you really see the pixels and work with it, that doesn't happen in photoshop (and mayeb we work more zoomed in in animation
- In animation (and because of the tvpaint destructive workflow) you usually transform multiple times in a row, degrading further the pixels. That doesn't happen in photoshop.
- Those algorythms work well on photos, cause there is a dependancy beetween areas and you have to keep your global coherence (so "extend" pixels accordingly). When working with lines, you want to have the same sharpness on the sides of the strokes. But it's not really possible, there is no informations when you transform the pixels, the standard algorythm for photos just doesn't want to create new informations cause it's not it's purpose (but hey there is different algorythm choices in photoshop so why not). You need a new algorythm specifically for lines, but then it really depends on the brush you're using...
Regarding PAP if it's a brand new algorythm specifically designed for lines it makes sense to me
I think tvpaint's algorythm is quiet standard and quiet old right now.